More problems.

2018 ACM-ICPC, Universidad Nacional de Colombia Programming Contest/D. Divorce.cpp

@@ -0,0 +1,174 @@
+/* Problem URL: https://codeforces.com/gym/101845/problem/D */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+struct pt {
+    ll x, y;
+
+    pt() = default;
+    pt(ll x, ll y): x(x), y(y) {}
+
+    friend istream &operator >> (istream &is, pt &a) {
+        is >> a.x >> a.y;
+        return is;
+    }
+
+    ll operator * (pt b) {
+        return x * b.x + y * b.y;
+    }
+
+    ll operator ^ (pt b) {
+        return x * b.y - y * b.x;
+    }
+
+    pt operator - (pt b) {
+        return pt(x - b.x, y - b.y);
+    }
+};
+
+ll sarea2(pt a, pt b, pt c)
+{
+    return (b - a) ^ (c - a);
+}
+
+int ccw(pt a, pt b, pt c)
+{
+    ll r = sarea2(a, b, c);
+    return (r > 0) - (r < 0);
+}
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int n, m;
+    cin >> n >> m;
+
+    V<pt> pol(n);
+    cin >> pol;
+
+    vl pref(n * 3);
+    nrep(i, 1, n * 3) {
+        pref[i] = pref[i - 1] + sarea2(pt(0, 0), pol[(i - 1) % n], pol[i % n]);
+    }
+
+    ll ans = 0;
+    while (m--) {
+        int l, r;
+        cin >> l >> r;
+        l--, r--;
+
+        if (l > r) {
+            swap(l, r);
+        }
+
+        if ((l + 1) % n == r) {
+            continue;
+        }
+
+        int l2 = r;
+        int r2 = l + n;
+
+        ll ar1 = abs(sarea2(pt(0, 0), pol[r], pol[l]) + pref[r] - pref[l]);
+        ll ar2 = abs(pref[r2] - pref[l2] + sarea2(pt(0, 0), pol[r2 % n], pol[l2 % n]));
+
+        rmax(ans, min(ar1, ar2));
+    }
+
+    cout << ans / 2.0 << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

2018 ACM-ICPC, Universidad Nacional de Colombia Programming Contest/F. UN Finals.cpp

@@ -0,0 +1,229 @@
+/* Problem URL: https://codeforces.com/gym/101845/problem/F */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    auto count = [&](string &a, int c[26]) {
+        repv(i, a) {
+            c[i - 'A']++;
+        }
+    };
+
+    V<tuple<int, ll, ll>> edges;
+    vvi graph(n + 28);
+    int sz = graph.size();
+
+    int s = 0;
+    int t = n + 27;
+
+    auto add_edge = [&](int u, int v, ll c) {
+        graph[u].push_back(edges.size());
+        edges.emplace_back(v, c, 0);
+        graph[v].push_back(edges.size());
+        edges.emplace_back(u, 0, 0);
+    };
+
+    vl pos(n);
+    rep(i, n) {
+        string a, b, c;
+        cin >> a >> b >> c;
+
+        add_edge(s, i + 1, 1);
+
+        int cc[26] = {0};
+
+        count(a, cc);
+        count(b, cc);
+        count(c, cc);
+
+        int ma = *max_element(cc, cc + 26);
+
+        rep(j, 26) {
+            if (cc[j] == ma) {
+                add_edge(i + 1, j + n + 1, 1);
+            }
+        }
+    }
+
+    int k;
+    cin >> k;
+
+    rep(i, 26) {
+        add_edge(i + n + 1, t, k);
+    }
+
+    vi lvl(sz, oo);
+    vi p(sz);
+
+    auto bfs = [&]() {
+        lvl[s] = 0;
+        queue<int> q;
+        q.push(s);
+
+        while (!q.empty()) {
+            auto i = q.front();
+            q.pop();
+
+            repv(id, graph[i]) {
+                auto [j, l, c] = edges[id];
+                if (l != c && lvl[j] > lvl[i] + 1) {
+                    lvl[j] = lvl[i] + 1;
+                    q.push(j);
+                }
+            }
+        }
+
+        return lvl[t] != oo;
+    };
+
+    function<ll(int, ll)> dfs = [&](int i, ll f) {
+        if (f == 0) {
+            return 0LL;
+        }
+
+        if (i == t) {
+            return f;
+        }
+
+        for (int &d = p[i]; d < graph[i].size(); d++) {
+            int id = graph[i][d];
+            auto &[j, l, c] = edges[id];
+
+            if (l == c || lvl[j] <= lvl[i]) {
+                continue;
+            }
+
+            ll fr = dfs(j, min(f, l - c));
+            if (fr == 0) {
+                continue;
+            }
+
+            c += fr;
+            auto &[_, __, c2] = edges[id^1];
+            c2 -= fr;
+
+            return fr;
+        }
+
+        return 0LL;
+    };
+
+    ll ans = 0;
+
+    while (1) {
+        fill(all(lvl), oo);
+        if (!bfs()) {
+            break;
+        }
+
+        fill(all(p), 0);
+        ll add = 0;
+        while ((add = dfs(s, OO)) != 0) {
+            ans += add;
+        }
+    };
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

2018 ACM-ICPC, Universidad Nacional de Colombia Programming Contest/I. Intense Bit Wheel.cpp

@@ -0,0 +1,128 @@
+/* Problem URL: https://codeforces.com/gym/101845/problem/I */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int n, m;
+    cin >> n >> m;
+
+    while (m--) {
+        ll num, k;
+        cin >> num >> k;
+
+        k %= n;
+
+        ll ans = 0;
+        int cur = 0;
+        int lim = n - k;
+        nrep(i, lim, n) {
+            ans |= ((num >> i) & 1) << cur;
+            cur++;
+        }
+        rep(i, lim) {
+            ans |= ((num >> i) & 1) << cur;
+            cur++;
+        }
+
+        cout << ans << '\n';
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

2024-2025 ICPC, NERC, Northern Eurasia Finals (Unrated, Online Mirror, ICPC Rules, Teams Preferred)/A. Adrenaline Rush.cpp

@@ -0,0 +1,157 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2052/A */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int n;
+    cin >> n;
+    vi p(n);
+    cin >> p;
+    reverse(all(p));
+
+    V<pair<int, int>> ans;
+    V<bool> us(n + 1);
+
+    // rep(i, n) {
+    //     int c = p[i];
+    //     for (int j = c - 1; j > 0; j--) {
+    //         if (us[j - 1]) {
+    //             continue;
+    //         }
+    //
+    //         ans.emplace_back(c, j);
+    //     }
+    //
+    //     for (int j = c + 1; j <= n; j++) {
+    //         if (us[j - 1]) {
+    //             continue;
+    //         }
+    //
+    //         ans.emplace_back(j, c);
+    //         ans.emplace_back(c, j);
+    //     }
+    // }
+
+    rep(i, n) {
+        int c = p[i];
+        us[c] = true;
+
+        for (int j = c - 1; j > 0; j--) {
+            if (us[j]) {
+                continue;
+            }
+            ans.emplace_back(c, j);
+        }
+
+        for (int j = 1; j <= n; j++) {
+            if (us[j]) {
+                continue;
+            }
+            ans.emplace_back(j, c);
+        }
+    }
+
+    cout << ans.size() << '\n';
+    repv(i, ans) {
+        cout << i.first << ' ' << i.second << '\n';
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1024 (Div. 1)/B. Quartet Swapping.cpp

@@ -0,0 +1,141 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2101/B */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+    vi p(n);
+    cin >> p;
+
+    vvi od(2);
+
+    auto cnt = [&](vi &p) {
+        int ans = 0;
+        ordered_set<int> ord;
+        rep(i, p.size()) {
+            ans += ord.size() - ord.order_of_key(p[i]);
+            ord.insert(p[i]);
+        }
+        return ans & 1;
+    };
+
+    rep(i, n) {
+        od[i & 1].push_back(p[i]);
+    }
+
+    bool pos = cnt(od[0]) != cnt(od[1]);
+
+    sort(all(od[0]), greater<>());
+    sort(all(od[1]), greater<>());
+
+    rep(i, n) {
+        p[i] = od[i & 1].back();
+        od[i & 1].pop_back();
+    }
+
+    if (pos) {
+        swap(p[n - 1], p[n - 3]);
+    }
+
+    cout << p;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1081 (Div. 2)/A. String Rotation Game.cpp

@@ -0,0 +1,118 @@
+/* Problem URL: https://codeforces.com/contest/2192/problem/A */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+    string a;
+    cin >> a;
+
+    int ans = 1;
+    int rep = 0;
+    nrep(i, 1, n) {
+        ans += a[i] != a[i - 1];
+        rep |= a[i] == a[i - 1];
+    }
+
+    cout << ans + rep - (rep && n > 1 && a.back() == a.front()) << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1081 (Div. 2)/B. Flipping Binary String.cpp

@@ -0,0 +1,129 @@
+/* Problem URL: https://codeforces.com/contest/2192/problem/B */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    vvi pos(2);
+    rep(i, n) {
+        char b;
+        cin >> b;
+        pos[b == '1'].push_back(i + 1);
+    }
+
+    int now = 0;
+    if (~pos[0].size() & 1) {
+        if (pos[1].size() & 1) {
+            cout << "-1\n";
+            return;
+        }
+        now = 1;
+    }
+
+    cout << pos[now].size() << '\n';
+    repv(i, pos[now]) {
+        cout << i << ' ';
+    }
+    cout << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1081 (Div. 2)/C. All-in-one Gun.cpp

@@ -0,0 +1,160 @@
+/* Problem URL: https://codeforces.com/contest/2192/problem/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    ll h, k;
+    cin >> n >> h >> k;
+
+    vl a(n);
+    ll sum = 0;
+    repv(i, a) {
+        cin >> i;
+        sum += i;
+    }
+
+    ll ans = h / sum * (k + n);
+    h %= sum;
+
+    if (h == 0) {
+        cout << ans - k << '\n';
+        return;
+    }
+
+    int lim = 0;
+    vl pref(n + 1);
+    rep(i, n) {
+        pref[i + 1] = pref[i] + a[i];
+    }
+
+    while (h - pref[lim] > 0) {
+        lim++;
+    }
+
+    ll ma = 0;
+    nrep(j, lim - 1, n) {
+        rmax(ma, a[j]);
+    }
+
+    int cur = oo;
+    rep(i, lim) {
+        int low = i;
+        int high = lim - 1;
+        int ans = lim;
+        while (low <= high) {
+            int mid = (low + high) >> 1;
+
+            if (pref[mid + 1] - a[i] + ma >= h) {
+                ans = mid + 1;
+                high = mid - 1;
+                continue;
+            }
+
+            low = mid + 1;
+        }
+
+        rmin(cur, ans);
+    }
+
+    cout << ans + cur << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1086 (Div. 2)/A. Bingo Candies.cpp

@@ -0,0 +1,132 @@
+/* Problem URL: https://codeforces.com/contest/2208/problem/A */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    vi c(n * n);
+    rep(i, n) {
+        rep(j, n) {
+            int a;
+            cin >> a;
+            c[a - 1]++;
+        }
+    }
+
+    if (n == 1) {
+        cout << "NO\n";
+        return;
+    }
+
+    int sz = n * n - n;
+
+    rep(i, n * n) {
+        if (c[i] > sz) {
+            cout << "NO\n";
+            return;
+        }
+    }
+
+    cout << "YES\n";
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1086 (Div. 2)/B. Cyclists.cpp

@@ -0,0 +1,150 @@
+/* Problem URL: https://codeforces.com/contest/2208/problem/B */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n, k, p, m;
+    cin >> n >> k >> p >> m;
+
+    list<pair<int, bool>> a;
+    rep(i, n) {
+        int c;
+        cin >> c;
+        a.emplace_back(c, i == p - 1);
+    }
+
+    int ans = 0;
+    while (1) {
+        auto choice = a.begin();
+        auto itr = next(choice);
+
+        nrep(i, 1, k) {
+            if (choice->second) {
+                break;
+            }
+
+            if (itr->second) {
+                choice = itr;
+                itr++;
+                continue;
+            }
+
+            if (itr->first < choice->first) {
+                choice = itr;
+            }
+
+            itr++;
+        }
+
+        if (choice->first > m) {
+            break;
+        }
+
+        auto now = *choice;
+        a.erase(choice);
+        ans += now.second;
+        m -= now.first;
+        a.emplace_back(now);
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1086 (Div. 2)/C. Stamina and Tasks.cpp

@@ -0,0 +1,123 @@
+/* Problem URL: https://codeforces.com/contest/2208/problem/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    V<pair<int, int>> a(n);
+    repv(i, a) {
+        cin >> i.first >> i.second;
+    }
+
+    reverse(all(a));
+
+    long double ans = 0;
+    rep(i, n) {
+        auto [c, p] = a[i];
+
+        rmax(ans, ans * (1 - p / 100.0L) + c);
+    }
+
+    cout << fixed << setprecision(10) << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1086 (Div. 2)/D1. Tree Orientation (Easy Version).cpp

@@ -0,0 +1,258 @@
+/* Problem URL: https://codeforces.com/contest/2208/problem/D1 */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    V<string> a(n);
+    cin >> a;
+
+    vvi graph(n);
+    vvi mult(n);
+    vvi inv(n);
+
+    rep(i, n) {
+        if (a[i][i] != '1') {
+            cout << "No\n";
+            return;
+        }
+
+        rep(j, n) {
+            if (i == j) {
+                continue;
+            }
+
+            if (a[i][j] == '0') {
+                continue;
+            }
+
+            rep(k, n) {
+                if (a[i][k] == '0' && a[j][k] == '1') {
+                    cout << "No\n";
+                    return;
+                }
+            }
+
+            graph[i].push_back(j);
+            inv[j].push_back(i);
+            mult[i].push_back(j);
+            mult[j].push_back(i);
+        }
+    }
+
+    vi st;
+    V<bool> frame(n);
+    V<bool> vis(n);
+
+    function<bool(int)> dfs = [&](int i) {
+        vis[i] = true;
+        frame[i] = true;
+
+        repv(j, graph[i]) {
+            if (frame[j]) {
+                return false;
+            }
+
+            if (vis[j]) {
+                continue;
+            }
+
+            if (!dfs(j)) {
+                return false;
+            }
+        }
+
+        st.push_back(i);
+
+        frame[i] = false;
+        return true;
+    };
+
+    function<void(int)> dfs2 = [&](int i) {
+        vis[i] = true;
+        repv(j, mult[i]) {
+            if (vis[j]) {
+                continue;
+            }
+
+            dfs2(j);
+        }
+    };
+
+    rep(i, n) {
+        if (vis[i]) {
+            continue;
+        }
+
+        if (!dfs(i)) {
+            cout << "No\n";
+            return;
+        }
+    }
+
+    fill(all(vis), false);
+    dfs2(0);
+
+
+    rep(i, n) {
+        if (!vis[i]) {
+            cout << "No\n";
+            return;
+        }
+    }
+
+    V<V<bool>> rem(n, V<bool>(n));
+
+    vvi act(n);
+    V<pair<int, int>> ans;
+
+    repv(i, st) {
+        repv(j, graph[i]) {
+            if (rem[i][j]) {
+                continue;
+            }
+
+            act[i].push_back(j);
+            act[j].push_back(i);
+            ans.emplace_back(i + 1, j + 1);
+            rem[i][j] = true;
+        }
+
+        repv(j, inv[i]) {
+            rep(k, n) {
+                rem[j][k] = rem[j][k] || rem[i][k];
+            }
+        }
+    }
+    fill(all(vis), false);
+
+    function<bool(int, int)> test = [&](int i, int p) {
+        vis[i] = true;
+        repv(j, act[i]) {
+            if (j == p) {
+                continue;
+            }
+
+            if (vis[j]) {
+                return false;
+            }
+
+            if (!test(j, i)) {
+                return false;
+            }
+        }
+
+        return true;
+    };
+
+    if (!test(0, 0)) {
+        cout << "No\n";
+        return;
+    }
+
+    cout << "Yes\n";
+    repv(i, ans) {
+        cout << i.first << ' ' << i.second << '\n';
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1087 (Div. 2)/A. Flip Flops.cpp

@@ -0,0 +1,126 @@
+/* Problem URL: https://codeforces.com/contest/2209/problem/A */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+        int n;
+        ll c;
+        ll k;
+        cin >> n >> c >> k;
+
+        vl a(n);
+        cin >> a;
+
+        sortv(a);
+        repv(i, a) {
+            if (i > c) {
+                break;
+            }
+
+            ll diff = c - i;
+
+            c += i + min(k, diff);
+            k -= min(k, diff);
+        }
+
+        cout << c << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1087 (Div. 2)/B. Array.cpp

@@ -0,0 +1,121 @@
+/* Problem URL: https://codeforces.com/contest/2209/problem/B */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+    vl a(n);
+    cin >> a;
+
+    rep(i, n) {
+        int c1 = 0;
+        int c2 = 0;
+        nrep(j, i + 1, n) {
+            c1 += a[j] > a[i];
+            c2 += a[j] < a[i];
+        }
+        
+        cout << max(c1, c2) << ' ';
+    }
+    cout << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1087 (Div. 2)/C. Find the Zero.cpp

@@ -0,0 +1,145 @@
+/* Problem URL: https://codeforces.com/contest/2209/problem/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    auto ask = [&](int i, int j) {
+        cout << "? " << i << ' ' << j << endl;
+        int ans;
+        cin >> ans;
+        return ans;
+    };
+
+    auto answer = [&](int i) {
+        cout << "! " << i << endl;
+    };
+
+    for (int i = 1; i <= n * 2 - 2; i += 2) {
+        int ans = ask(i, i + 1);
+        if (ans == 1) {
+            answer(i);
+            return;
+        }
+    }
+
+    int p1 = n * 2 - 3;
+    int p2 = n * 2 - 2;
+    int p3 = n * 2 - 1;
+    int p4 = n * 2;
+
+    int ans = ask(p1, p3);
+    if (ans == 1) {
+        answer(p1);
+        return;
+    }
+
+    ans = ask(p2, p3);
+    if (ans == 1) {
+        answer(p2);
+        return;
+    }
+
+    answer(p4);
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 867 (Div. 3)/F. Gardening Friends.cpp

@@ -0,0 +1,174 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1822/F */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+    ll k, c;
+    cin >> k >> c;
+
+    vvi graph(n);
+    rep(i, n - 1) {
+        int a, b;
+        cin >> a >> b;
+        a--, b--;
+        graph[a].push_back(b);
+        graph[b].push_back(a);
+    }
+
+    vi dis(n);
+    vi dp(n);
+    dis[0] = -1;
+
+    function<int(int, int)> dfs = [&](int i, int p) {
+        dis[i] = dis[p] + 1;
+        repv(j, graph[i]) {
+            if (j == p) {
+                continue;
+            }
+
+            rmax(dp[i], dfs(j, i) + 1);
+        }
+
+        return dp[i];
+    };
+
+    dfs(0, 0);
+
+    function<void(int, int)> reroot = [&](int i, int p) {
+        ll c1 = -1;
+        ll c2 = -1;
+        repv(j, graph[i]) {
+            if (dp[j] + 1 > c1) {
+                c2 = c1;
+                c1 = dp[j] + 1;
+                continue;
+            }
+
+            if (dp[j] + 1 > c2) {
+                c2 = dp[j] + 1;
+            }
+        }
+
+        ll ans = c1;
+
+        repv(j, graph[i]) {
+            if (j == p) {
+                continue;
+            }
+            dp[i] = dp[j] + 1 == ans ? c2 : c1;
+            reroot(j, i);
+        }
+
+        dp[i] = ans;
+    };
+
+    reroot(0, 0);
+
+    ll ans = 0;
+    rep(i, n) {
+        rmax(ans, dp[i] * k - dis[i] * c);
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 913 (Div. 3)/D. Jumping Through Segments.cpp

@@ -0,0 +1,154 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1907/D */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    V<pair<ll, ll>> a(n);
+    repv(i, a) {
+        cin >> i.first >> i.second;
+    }
+
+    ll low = 0;
+    ll high = 1e9;
+    ll ans = 1e9;
+    while (low <= high) {
+        ll mid = (low + high) >> 1;
+
+        ll l = 0;
+        ll r = 0;
+
+        bool pos = true;
+
+        repv(i, a) {
+            ll l1 = l - mid;
+            ll l2 = l + mid;
+            ll r1 = r - mid;
+            ll r2 = r + mid;
+
+            rmax(l1, i.first);
+            rmin(l2, i.second);
+            rmax(r1, i.first);
+            rmin(r2, i.second);
+
+            l = min(l1, r1);
+            r = max(l2, r2);
+
+            if (l > r) {
+                pos = false;
+                break;
+            }
+        }
+
+        if (pos) {
+            ans = mid;
+            high = mid - 1;
+            continue;
+        }
+
+        low = mid + 1;
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 943 (Div. 3)/G1. Division + LCP (easy version).cpp

@@ -0,0 +1,163 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1968/G1 */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+struct hash_string {
+    static vl p;
+    static ll m;
+    static ll b;
+    vl hash;
+
+    hash_string(string &a) {
+        while (p.size() <= a.size()) {
+            p.push_back(((__int128)p.back() * b) % m);
+        }
+
+        hash.resize(a.size() + 1);
+        rep(i, a.size()) {
+            hash[i + 1] = ((__int128)hash[i] * b + a[i]) % m;
+        }
+    }
+
+    ll gethash(int l, int r) {
+        return ((hash[r + 1] - (__int128)hash[l] * p[r - l + 1]) % m + m) % m;
+    }
+};
+
+vl hash_string::p = {1};
+ll hash_string:: m = (1LL << 61) - 1;
+mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
+ll hash_string:: b = uniform_int_distribution<>()(rng);
+
+void solve()
+{
+    int n, l, r;
+    cin >> n >> l >> r;
+    string a;
+    cin >> a;
+
+    hash_string ah(a);
+
+    int low = 1;
+    int high = n;
+    int ans = 0;
+    while (low <= high) {
+        int mid = (low + high) >> 1;
+
+        int c = 1;
+        for (int i = mid; i + mid - 1 < n; i++) {
+            if (ah.gethash(0, mid - 1) == ah.gethash(i, i + mid - 1)) {
+                c++;
+                i += mid - 1;
+            }
+        }
+
+        if (c >= l) {
+            ans = mid;
+            low = mid + 1;
+            continue;
+        }
+
+        high = mid - 1;
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 964 (Div. 4)/F. Expected Median.cpp

@@ -0,0 +1,149 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1999/F */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+const ll mod = 1e9 + 7;
+
+constexpr int MAXN = 2e5 + 10;
+ll fact[MAXN];
+ll inv[MAXN];
+ll invf[MAXN];
+
+void pre()
+{
+    fact[0] = 1;
+    nrep(i, 1, MAXN) {
+        fact[i] = fact[i - 1] * i % mod;
+    }
+
+    inv[1] = 1;
+    nrep(i, 2, MAXN) {
+        inv[i] = (mod - mod / i) * inv[mod % i] % mod;
+    }
+
+    invf[0] = 1;
+    nrep(i, 1, MAXN) {
+        invf[i] = invf[i - 1] * inv[i] % mod;
+    }
+}
+
+ll comb(ll n, ll k) {
+    return fact[n] * invf[k] % mod * invf[n - k] % mod;
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n, k;
+    cin >> n >> k;
+    vi a(n);
+    cin >> a;
+
+    ll c0 = count(all(a), 0);
+    ll c1 = count(all(a), 1);
+
+    ll ans = 0;
+    nrep(i, (k + 1) >> 1, k + 1) {
+        ll o = i;
+        ll z = k - i;
+
+        if (c0 < z || c1 < o) {
+            continue;
+        }
+
+        (ans += comb(c1, o) * comb(c0, z) % mod) %= mod;
+    }
+    
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Teza Round 1 (Codeforces Round 1015, Div. 1 + Div. 2)/C. You Soared Afar With Grace.cpp

@@ -0,0 +1,163 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2084/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+    vi a(n);
+    vi b(n);
+    cin >> a >> b;
+
+    int c = 0;
+    int p;
+
+    map<pair<int, int>, int> s;
+    rep(i, n) {
+        s[{a[i], b[i]}] = i;
+        if (a[i] == b[i]) {
+            c++;
+            p = i;
+        }
+    }
+
+    if ((c > 0 && (~n & 1)) || (c != 1 && (n & 1))) {
+        cout << "-1\n";
+        return;
+    }
+
+    rep(i, n) {
+        if (!s.count({b[i], a[i]})) {
+            cout << "-1\n";
+            return;
+        }
+    }
+
+    V<pair<int, int>> ans;
+
+    if (c && p != (n >> 1)) {
+        ans.emplace_back(p + 1, (n >> 1) + 1);
+        swap(a[p], a[n >> 1]);
+        swap(b[p], b[n >> 1]);
+        swap(s[{a[p], b[p]}], s[{a[n >> 1], b[n >> 1]}]);
+    }
+
+    rep(i, n >> 1) {
+        int rev = n - i - 1;
+        auto itr = s.find({b[i], a[i]});
+
+        if (itr->second == rev) {
+            continue;
+        }
+
+        ans.emplace_back(itr->second + 1, rev + 1);
+        auto itr2 = s.find({a[rev], b[rev]});
+        swap(a[rev], a[itr->second]);
+        swap(b[rev], b[itr->second]);
+        swap(itr->second, itr2->second);
+    }
+
+    cout << ans.size() << '\n';
+    repv(i, ans) {
+        cout << i.first << ' ' << i.second << '\n';
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

problemlist.md

@@ -47,6 +47,10 @@ A little collection of interesting problems that I randomly decided to do.
 
 	Interesting reroot problem, there's not much for me to say about it.
 
+- [F. Gardening Friends](https://codeforces.com/problemset/problem/1822/F)
+
+	Very standard reroot problem, but interesting as an exercise.
+
 ## DP
 
 - [D. World is Mine](https://codeforces.com/problemset/problem/1987/D)
@@ -133,6 +137,10 @@ A little collection of interesting problems that I randomly decided to do.
 	it's interesting to think about regardless, can also be solved with a binary search, but
 	it's not required.
 
+- [F. Expected Median](https://codeforces.com/problemset/problem/1999/F)
+
+	Kinda introductory combinatory problem, but interesting as an exercise.
+
 ## DSU
 
 - [https://codeforces.com/problemset/problem/1985/H1](https://codeforces.com/problemset/problem/1985/H1)
@@ -151,3 +159,9 @@ A little collection of interesting problems that I randomly decided to do.
 	
 	Interesting problem to think about, good introduction to divide and conquer in my opinion and
 	can be used as a bridge to segment trees.
+
+## String
+
+- [G1. Division + LCP (easy version)](https://codeforces.com/problemset/problem/1968/G1)
+
+	Can be solved in a lot of ways, but I find hashing with binary search simpler.